Add links to select YouTube videos demonstrating GitLab features to docs

doc/user/discussions/index.md

@@ -53,6 +53,8 @@ persist through a commit ID change when:
 - force-pushing after a rebase
 - amending a commit
 
+This functionality is also demonstrated in the video [How to use Merge Request Commit Discussions](https://www.youtube.com/watch?v=TviJH6oRboo).
+
 To create a commit diff discussion:
 
 1. Navigate to the merge request **Commits** tab. A list of commits that

doc/user/project/labels.md

@@ -32,6 +32,8 @@ An issue, epic, or merge request cannot have two scoped labels with the same key
 For example, if an issue is already labeled `priority::3` and you apply the label `priority::2` to it,
 `priority::3` is automatically removed.
 
+This functionality is demonstrated in a video titled [Use scoped labels in GitLab 11.10 for custom fields and custom workflows](https://www.youtube.com/watch?v=4BCBby6du3c).
+
 ### Labels with multiple colon pairs
 
 If labels have multiple instances of `::`, the longest path from left to right, until the last `::`, is considered the "key" or the "scope".